Manufacture of artificial textile materials



Patented Nov. 10, 1942 UNITED STATES PATENT GFFECE MANUFACTURE OFARTIFICIAL TEXTILE MATERIALS No Drawing. Application November 29, 1939Serial No. 306,704 In Great Britain December 12, 1938 6 Claims.

This invention relates to improvements in the manufacture of artificialtextile materials in yarn, fabric or other form, and in particular tothe improvement of the properties of textile materials containingcellulose acetate or other orame derivative of cellulose.

Various attempts have been made to improve the properties of textilematerials containing partially esterified or etherified organicderivatives of cellulose by further esterification, particularly with aview to rendering them more resistant to water and heat and to modifyingtheir solubility in organic solvents. Thus, it has been proposed toemploy inorganic acid derivatives, for example thionyl chloride, silicontetrachloride and phosphorous oxychloride and anhydrides or halides ofmono and poly-carboxylic acids, both of the aliphatic and aromaticseries, for example acetic acid, benzoic acid, succinic acid, adipicacid and phthalic acid.

Whilst these known methods are generally capable of effecting a certainamount of esterification of the cellulose derivative materials, it hasbeen found that they are subject to various disadvantages. For example,esterification may be accompanied by a serious deterioration in thetextile properties of the materials treated, for example the tenacity orextension, particularly when acid halides are employed. In order toavoid this deterioration it has been proposed in some cases toneutralise the hydrohalide acid formed and in other cases to use theacid halides diluted with gaseous media. It has also been proposed todry the cellulose derivative materials in order to reduce the degradingaction of the hydrohalide acid.

If a cool iron at a temperature, for example, of about ZOO-220 C. isemployed, no trouble is experienced with normal cellulose acetatefabrics, but the principal object of the present invention is to make itpossible to use a hotter iron and to avoid glazing, scorching or othertroubles.

By subjecting cellulose acetat materials to acetylation their meltingpoint may be increased to about 300 C. but this is not alwaysaccompanied by an equally great improvement in the ironing point.Attempts to improve the ironing point by esterifica-tion withdicarboxylic acid an hydrides and chlorides have not yielded anybetironing point, can be obtained by esterification with halides ofpolybasic acids if a substantially higher temperature is employed foresterification than has hitherto been employed in processes of furtheresterification with derivatives of monoor poly-basic acids. In order toobtain these improved results, it has been found necessary to effectesterification at a temperature above C., the best results beingobtained, in general, at a temperature of C. to 170 C., e. g. or C. Itwould have been expected that at such high temperatures the hydrohalideacid formed would have a destructive effect on the materials subjectedto esterification and it is surprising that this has been found not tobe the case.

The process is applicable to textile materials in general which containorganic derivatives of cellulose, particularly organic derivatives ofcellulose containing about 2-2.5 substituent radicles per C6Hl005nucleus. The materials may for example be staple fibres or staple fibreor continuous filament yarns in the form of hanks or present in woven,knitted or netted fabrics.

The halides which it is preferred to employ are those of adipic acid andphthalic acid, particularly the chlorides. Examples of other halideswhich may be employed are oxalyl, melonyl, and succinyl chlorides andcarbonyl, thionyl and sulphonyl chlorides.

Esterification in accordance with the process of the present inventionmakes it possible to improve very considerably the ironing point of thematerials. Thus, for example, While processes previously described usinghalides of polybasic acids only yield products having an ironing pointof about 220230 C., which is practically the same as that of thestarting materials, by means of the present process an ironing point of280-300 C. or even more may be obtained. The melting point of theproducts may be raised for example to 340 C. or more. The process alsorenders the materials more water-repellent and less soluble or eveninsoluble in organic solvents.

The ironing point referred to in this specification is the maximumtemperature of the base of an iron of the modern household electricaltype which can be moved over a fabric at a speed of one foot per secondwithout scorching or weakening the fabric.

The materials to be esterified are preferably freed from any oil orother conditioning agent by scouring and drying.

The esterification may be effected by heating the cellulose derivativematerials in a solution of the acid halide dissolved in an organicliquid which is a non-solvent for the materials and it has been foundthat the nature of this liquid, though it does not appear to take anypart in the reaction, is also of importance. The organic liquids whichhave been found to be of particular value are hydrocarbons, particularlykerosene, toluene, xylene and mesitylene. Mixtures of organic liquids,for example a mixture of 60% kerosene and 40% xylene, may also beemployed. The concentration of the acid halide in the organic liquid maybe low, for example 1 or 2%, or considerably higher, for example 10, orThe volume ratio of liquid medium to textile materials should be high,for example, be 40 or :1, and may with advantage be even higher, e. g.100:1 or 500:1, particularly if the production of products of hightenacity is important.

The esterification medium may also contain a proportion of polybasicacid anhydride, e. g. about 24%.

In order to obtain products having the optimum properties as regardstenacity, it is desirable that the materials employed, including boththe fabric or other to be esterified and the reagents, should beanhydrous. Fabrics and other materials may be dried for example in a hotair oven, while xylene or other diluent may be dried by treatment with asuitable reagent, for example anhydrous sodium sulphate. It is alsodesirable that the hydrohalide acid, a substantial amount of which isformed in the early stages of the reaction, should be allowed to escapeas quickly as possible. Fabrics may, for example, be treated on a.winch, at least in the early stages of the reaction, in order to avoidthe formation of pockets of hydrohalide acid. In the later stages theamount of acid evolved is generally less and such precautions becomeless necessary. The removal of hydrohalide acid formed may be assistedby bubbling nitrogen or other inert gas through the liquid during thereaction.

The reaction may be carried out in a closed vessel. In general, however,it is better to remove hydrohalide acid as it is evolved. This may beeffected by the use of an apparatus fitted with a refiux condenser, thereflux conditions being such that hydrohalide acid split off escapes byway of the condenser while the other reagents present in the reactionmedium are condensed and returned to the reaction vessel. Preferably,however, the whole of the distillate is removed and condensed. Inaddition to their other advantages, the organic liquids referred to areespecially valuable, since they boil Within the temperature range whichhas been found to give the best results and control of the temperatureconditions is thus facilitated.

Products having substantially improved properties may be obtained bycarrying out the esterification process for a comparatively shortperiod, for example 1530 minutes, or even less, e. g. 5 minutes, and ingeneral it is found that a longer period than one or two hours is notnecessary and does not result in any substantial further improvement inthe properties of the products.

After completion of the reaction, the materials should be well washed tofree them from the constituents of the reaction medium. For example,they may be washed first with a liquid which is miscible with theconstituents of the esterification medium. When xylene is used asnon-solvent diluent a suitable liquid is acetone or carbontetrachloride. The materials may then be washed successively with adilute solution of sodium carbonate, with dilute acid, for exampledilute acetic acid, and with water.

The following are examples of the production of textile materials havingan improved ironing point and other improved properties according to theprocess of the present invention:

Example 1 Hanks of cellulose acetate yarn having a high tenacityobtained by stretching cellulose acetate yarn in wet steam atsuperatmosphere pressure are scoured and dried and are then immersed inan esterification medium containing 1% of adipyl chloride and 99% oftoluene, the volume ratio being 50:1. They are boiled for about 2-5minutes and are then washed with carbon tetrachloride, air-dried andwashed with 1% of sodium carbonate solution at 25 C. for about 20minutes and then washed in water. Finally they are washed in cold 1%acetic acid for about 5 minutes, then in hot water and dried at about110 C.

Example 2 A woven fabric made of yarn of commercial acetone-solublecellulose acetate is scoured and dried and then immersed in anesterification medium containing 2% of adipyl chloride and 98% ofxylene, the volume ratio being 50: 1. It is then heated for about 30minutes at 140 C. On completion of the reaction the fabric is washedwith boiling acetone and dried. It is then secured in an alkaline soapbath, washed with water and again dried.

Example 3 A woven fabric made of yarns of commercial acetone-solublecellulose acetate is scoured and dried and is then immersed in anesterification medium containing 20% or phthalyl chloride and ofmesitylene, the volume ratio being 50:1. It is then heated for 2 hoursat about 165 C. On completion of the reaction the fabric is washed inbenzene, air dried, immersed in a 1% solution of sodium carbonate at 25C. for about 20 minutes and then washed in water. It is next washed incold 1% acetic acid for about 5 minutes, washed in hot water and driedat about 110 C.

Example 4 Example 5 A woven fabric made of yarns of commercialacetone-soluble cellulose acetate is scoured and dried and is thenimmersed in an esterification medium consisting of 10% of succinylchloride and of toluene, the volume ratio of medium to fabric being50:1. The materials are boiled in the medium for 3 hours. At thecompletion of the reaction the fabric is washed in benzene, air dried,immersed in a 1% solution of sodium carbonate at 25 C. for about 20minutes and then washed in water. It is then Washed in cold 1% aceticacid for about 5 minutes, washed in hot water and dried at about C.

Example 6 A woven fabric made of yarns of commercial acetone-solublecellulose acetate is scoured and dried and is then immersed in anesterification medium containing 10% thionyl chloride, 5% pyridine and85% of toluene, the volume ratio being :1. It is then boiled for 3hours. On completion of the reaction the fabric is washed and dried asdescribed in Example 5.

Example 7 An undyed fabric made of cellulose acetate yarn is turned by awinch in a bath of the following composition:

Per cent Xylene Phthalyl chloride 3 Phthalic anhydride 2 The bath iskept boiling at about 140 C. and the winch treatment is continued for 1hour. The fabric is then removed from the winch and completely immersedin the boiling bath for 3 hours. On removal from the bath, it is plungedimmediately into boiling acetone to free it as rapidly as possible fromthe constituents of the reaction medium and is finally given anantistatic finish of 1% wax from an acetone solution. The most suitablewax for this purpose has been found to be japan wax. If shrinkage occursduring the reaction, the fabric may, after esterification, be stretchedto its original dimensions by stentering.

The resistance of the fabric to boiling water and boiling soap solutionsis greatly improved and it can be subjected to treatment with such rsolutions for considerable periods without damage or delustringoccurring. The esterified product can be dyed in the ordinary manner,for example with dispersions of water-insoluble dyestufis. On account ofthe resistance to delustring, dyeing may be carried out at the boil andimproved fastness thus obtained.

In each of the above examples heating is effected using an ordinarycondenser, so that the distillate containing hydrohalide acid is notreturned to the esterification medium. The products obtained areinsoluble in acetone and chloroform and have a considerably increasedmelting and safe ironing point. The organic derivative of cellulosematerials for which the process is particularly valuable are celluloseacetate materials, especially those made of acetone-soluble celluloseacetate. Other organic derivatives of cellulose materials which may betreated are materials containing cellulose propionate, butyrate orbenzoate, or ethyl or butyl cellulose.

Having described our invention, what we desire to secure by LettersPatent is:

1. Process for improving the properties of artificial filaments, yarnsand other textile materials containing organic derivatives of cellulosewhich contain free hydroxy groups, which comprises esterifying them witha dicarboxylic acid halide dissolved in an organic liquid which is anonsolvent for said organic derivatives of cellulose at a temperatureabove C. under such conditions that their structure is retained.

2. Process for improving the properties of artificia1 filaments, yarnsand other textile materials containing acetonesoluble cellulose acetate,which comprises esterifying them at a temperature above 100 C. with asolution of a dicarboxylic acid chloride in a solvent medium comprisinga liquid hydrocarbon which is a non-solvent for said cellulose acetateunder such conditions that their structure is retained.

3. Process for improving the properties of artificial filaments, yarnsand other textile materials containing acetone-soluble celluloseacetate, which comprises esterifying them at a temperature between andC. with an esterification medium comprising adipyl chloride dissolved ina liquid hydrocarbon which is a non-solvent for said cellulose acetateunder such conditions that hydrochloric acid formed is removed from theesterification medium, the volume ratio of esterification medium totextile materials being at least 50:1.

4. Process for improving the properties of artificial filaments, yarnsand other textile materials containing acetone-soluble celluloseacetate, which comprises esterifying them at a temperature between 110and 170 C. with an esterification medium comprising phthalyl chloridedissolved in a liquid hydrocarbon which is a nonsolvent for saidcellulose acetate under such conditions that hydrochloric acid formed isremoved from the esterification medium, the volume ratio ofesterification medium to textile materials being at least 50: 1.

5. Process for improving the properties of artificial filaments, yarnsand other textile materials containing acetone-soluble celluloseacetate, which comprises esterifying them at a temperature between 110and 170 C. with an esterification medium comprising succinyl chloridedissolved in a liquid hydrocarbon which is a nonsolvent for saidcellulose acetate under such conditions that hydrochloric acid formed isremoved from the esterification medium, the volume ratio ofesterification medium to textile materials being at least 50:1.

6. Process for improving the properties of artificial filaments, yarnsand other textile materials containing acetone-soluble celluloseacetate, which comprises esterifying them with a dicarboxylic acidhalide dissolved in toluene at a temperature above 100 C. under suchconditions that their structure is retained.

HENRY DREYFUS. ROBERT WIGHTON MONCRIEFF.

